1. Field of the Invention
This invention relates to a matte film of the type that lines, characters, etc., can be drawn or written thereon and which can be revised or erased (hereinafter, the film is referred to as a drafting film). More particularly, the invention relates to a drafting film comprising a hydrophobic support having coated on one or both surfaces thereof matte layers wherein lines, characters, etc., can be directly drawn or written on the matte layer and easily revised or erased or further reproductions composed of wash-off relief images formed on the matte layer can be easily revised or erased by an eraser. Furthermore, the invention relates to a wash-off type photographic material using the above-described drafting film as the support.
2. Description of the Prior Art
A matte film generally comprises a low shrink hydrophobic support having formed thereon a matte layer containing a matting agent such as silicon dioxide, titanium dioxide, a glass powder, etc. Such a matte film can be used as it is for drawing or can be used as a support for a wash-off type photographic film comprising a photosensitive silver halide emulsion layer on the matte layer, which is used in such a manner that after imagewise exposing and developing the photographic film, non-image portions are washed off from the matte layer.
A matte film is required to have various properties for satisfactory use thereof, among which the following two properties are most important.
(1) The film must have excellent tensile strength, tear resistance, and bending strength, and undergo low curing and low dimensional deformation under the influence of temperature and/or humidity.
(2) The film must have good adaptability for drawing or writing with a drawing ink, pencil, etc., and also show good erasability at the case of erasing with an eraser, etc., after drawing or writing.
This invention is pertinent particularly to an improvement of the adaptability for drawing or writing and for revising or erasing as per property (2) above.
As binders for conventional matte layers of matte films, there are known vinylidene chloride copolymers (e.g., British Pat. No. 1,047,697), polymethyl methacrylate (e.g., U.S. Pat. No. 3,353,958), polyesters or polyester amide (e.g., U.S. Pat. No. 3,627,563, cellulose acetate (e.g., Japanese Patent Publication No. 48844/74), cellulose esters and polyesters (e.g., Japanese Patent Publication No. 39414/74), etc. However, in the case of using matte layers composed of binders as described above, it frequently happens that when lines or characters drawn or written with a pencil are erased with an eraser, dark traces of pencil writing remain on the matte layers to make erasing imperfect or, when the erasing force with an eraser is increased, the matte layers are scraped off.